The CW Reveals That "The Flash" Will Only Have 6 Episodes In Season 2 Then Will End As Series Finale

The Flash's Starlabs maybe knew how to harness super powers but they weren’t strong enough to save their TV series. CW's The Flash will be cancelled after the sixth episode in season 2.

The series had a decent debut last October with a 3.2 rating in the 18-49 demographic and 10.69 million total viewers. Unfortunately, the ratings didn’t stay at that level and dropped by 16% in week two and then 15% in week three. The numbers kept declining and went as low as a 1.2 demo rating and just 4.26 million viewers in March.
The network changed the order of some of the episodes and by then it was clear by that point that the show was finished according to the staff.

Hopefully, at some point, the producers will share what they had planned for the future of the series even though fans may never get to see it, but there is hope as there's been talks of Netflix picking it up.